Improvement in safety-valvs



diuitell 'Staten atwt1ijiire NIOHOLAs'rHOMA's, or OHIoAcO, ILLrNOIs.

Lett-ers Patent No. 107 ,305,l dated September 13, 18.70. y

rMRov'r-.MENT IN SAFETY-VALVE.

The Schedule referred to in these Letters Patent and making part of the same To all whom it may concern.-

Be it known that I, NICHOLAS THOMAS, of Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Safety- Valves; and I do hereby declare thelfollowing to be a full, clear, `and exact description thereof, which will the ca'se.

Similar letters of reference indicate corresponding parts in the several figures of the drawings.

It consists, first, in the construction of two hollow cylinders, one within the other, and so placed within the dome or steam-space of a4 boiler as to project downward therein, or in such a manner` as to be in direct communication with the steam, the outer cylinder being provided with perforations which admit steam into the space between the cylinders, and having, also, two seats forthe reception of the inner cylindcr,.whicl1 slides within the outer cylinder, constitut-ing a double-seat valve, whereby, as the valve is raised :from its seats, additional surface is exposed to the action of the steam, which then has afree and clear exit from the boiler, thereby preventing accident from explosion.

It consists', secondly, in suspending the outer cyl-v inder or shell within the boiler, or within a drum or case attached to the boiler in `such a manner that its lower end shall be free from contact with the boiler, whereby it is permitted to expand in proportion to the expansion of the valve, so that the latter shall lit both its seats equally under all circumstances.

In double-seated safety-valves,- as ordinarily constructed, the lower seat is supported from some part of the boiler in such a manner that it cannot expand vequally with the valve, and, as a consequence, the latter does not seatitself evenly, but permits the escape of' steam.

It consists, lastly, in alifting-device or handle, combined with the valve, thevalve-case, and weighted lever, whereby the valve may be lifted but cannot be held down, and whereby, also,` movements of the weighted lever are unobstructed.

In the accompanying drawings- A is the outer cylinder, having a ange, B, at or near its upper end, by which it is suspended from the case O, aixed to a boiler in such a manner as to be surrounded by steam. y

If desired, the case C may be dispensed with, and the cylinder suspended by its flange directly within the boiler.

The sides of the outer cylinder' are perforated, as shown at a a., for the purpose of admitting steam to the annular chamber or space D surrounding the valve.

E is an auxiliary chamber, and

11 F are the valve-seats in the outer cylinder.

G is the double-seated valve or hollow inner cylinder, provided with the anges b b, which are adapted to-tit the seats 11 F of the outer cylinder.

d is the large open space in the valve G, through which the steam entering at the lower valve-seat makes its exit.

ff are guides or projections formed upon themiddleand lower end ot' the valve, by which the latter is retained in position during its movements within the outer cylinder.

In the upper end of the valve is tted a loose pin, H, having its head notched to receive the fulcrum g of the weighted lever I, which holds thevalve to its seats.

` The shorter arm of the lever bears against a notched stud, 71., of the case K. rlhis case, by which thevalve is made a lock safety-valve, is composed of a rectangular box divided longitudinally into two parts, L and L. The lower part, L, is secured firmly, by means of screws or bolts It, to the case C, and both parts are fitted together by a dovetail connection, l,

' being held to each other by screws or bolts, m.

` The end L" of the part or top L over the valve is adapted for removal to permit access to the, valve without removing the entire top.

These two parts are secured together' by the screws or bolts n, through which may be fitted a suitable look, to prevent their being separated improperly ailier the valve has been set to the required pressure of steam. Y

M is a handle or lifting-rod passing through the top of the case K, and attached atits lower end to ayoke, N, whose slotted sides fit over lateral pins, o, upon 'the upper end of the valve, as shown in iig.2.

By lifting upon the handle, the valve can, `from time to time, be raised from its seats, to prevent its bccomingiixed to the latter or clogged by sediment.`

By reason of the slots -in the side of the yoke, it will be secu that the valve cannot kbe held down by applying weights or other force to the handle, but will rise independently of the same under suieient pressure of steam from the boiler.

,lhc operation of my invention is as follows:

'lhe cylinders A G being attached to the boiler as previouslymentioned, the steam enters through the perforations a a, filling the annular chamber D and pressinglr agaiustthe upper shoulder b of' the valve. N ow, as the force exerted by the steam on the valve exceeds the working pressure, the. valve G will be raised from its seats, and the surplus steam permitted to escape from the boiler through the circular space between the cylinders, as well'as through the large open interior of the Valve, by means ol' which the pressure of the ste-am is regulated, and accident from explosion prevented, as nearly double the quantity ot' steam-is'permitted to escape as compared with the ordinary valj'e.

The course of the escaping steam is shown by the arrows, iig; 1.

By suspending the cylinder' A within the boiler, as shown, its lower end is -free, lso that it can expand in proportion to the expansion of -the valve G,so that thelatter shall at all times t both seats equally.

My improved valve is not only effective as a safetyvulve, but can with equal ecienoy be employed as a throttle, puppet., or pump-valve, or, in fact, to any position where a liftevalve is required.

4. The combination of the handle M and yoke N withthe doubleseat valve, G, weighted lever I, and

ease K, substantially as described,- for the purpose specified. NICHOLAS THOMAS.

Witnesses:

Y J 01m A. SILEXCE, L. N. FARWELL. 

